Assume they'll enforce it since the law is due to safety (and not ease as someone else posted). If it was dark and rainy that's even more reason to not back out onto a street so that factor would tend to work against your argument. The picture someone else posted indicates the charger could be used with your parking within the rules so that's less than helpful, too. The reviewers will also know that the cable could have been crossed over your vehicle--not unlike fueling at gas stations.What I don't know is if they're going to enforce the back-in rule regardless of whether I was charging at all.
So unfortunately your situation is almost certainly going to be deemed a convenience issue and not one where you were required to break the parking laws (the usual threshold they'd want to see before dismissing the ticket).